Temperature controlled short duration ablation with resistive heating

Abstract

A method, including performing an ablation of tissue using a first high RF power for a short duration, suspending RF power for a predetermined period, and using a second high RF power for a short duration forming lesions with greater surface area and greater depth through resistive heating and thermal latency. High RF power may range between 75-95 W and short duration may range between 4-5 seconds.

1 . A system for ablation, comprising:
 a catheter having an ablation electrode configured for tissue contact; and   a controller configured to deliver pulsed ablation energy to the ablation electrode, the pulsed ablation energy comprising an ablation session of a predetermined total duration of time less than about 18 seconds, and comprising:
 a first pulse of resistive heating applied to the tissue by the ablation energy via the ablation electrode within a range of about 75 W-95 W for a first duration of about 4 seconds; 
 a suspension of the application of ablation energy to the ablation electrode for a second duration no greater than 10 seconds; 
 a measurement of temperature of the tissue at least every 33 ms at a depth of about 3 mm to determine dissipation of about 90% of heat of the tissue within about 4 seconds; and 
 a second pulse of resistive heating by the ablation energy via the electrode within the range of about 75 W-95 W for a third duration of about 4 seconds to the lesion. 
   
     
     
         2 . The system of  claim 1 , wherein the controller is configured to deliver the first pulse such that a lesion with a depth of about 3.5 mm is formed in the tissue. 
     
     
         3 . The system of  claim 1 , wherein the controller is configured to deliver the second pulse such that depth of a lesion in the tissue formed by the first pulse is increased to about 4.5 mm into surrounding tissue. 
     
     
         4 . The system of  claim 2 , wherein the controller is configured to deliver the second pulse such that the depth of the lesion is increased to about 4.5 mm into surrounding tissue. 
     
     
         5 . The system of  claim 1 , wherein the ablation session further comprises a measurement of impedance of the tissue every 500 ms. 
     
     
         6 . The system of  claim 1 , wherein the controller is configured to apply the first pulse of resistive heating such that a rate of temperature increase of the tissue in the first duration is generally linear, the controller configured to determine the rate of temperature increase of the tissue from the measurements of temperature. 
     
     
         7 . The system of  claim 1 , wherein the controller is configured to apply the first pulse of resistive heating such that a rate of temperature increase of the tissue in the first duration is greater than a rate of temperature decrease of the tissue in the second duration, the controller configured to determine the rate of temperature increase of the tissue from the measurements of temperature. 
     
     
         8 . The system of  claim 1 , wherein the controller is configured to deliver the ablation session over the predetermined total duration of time of less than about 13 seconds. 
     
     
         9 . The system of  claim 1 , wherein the controller is configured to deliver the first pulse and the third pulse of the ablation energy at about 90 W. 
     
     
         10 . The system of  claim 1 , wherein the catheter comprises a plurality of temperature sensors configured to detect the temperature of the tissue. 
     
     
         11 . The system of  claim 10 , wherein the controller comprises a temperature module configured to receive signals from the plurality of temperature sensors, and the measurement of the temperature of the tissue at least every 33 ms comprises calculating via the temperature module the maximum measured temperature value of the plurality of temperature sensors. 
     
     
         12 . The system of  claim 1 , wherein the controller comprises a power control module configured to deliver the ablation energy to the ablation electrode. 
     
     
         13 . The system of  claim 12 , wherein:
 the controller comprises a temperature module configured to receive signals from the plurality of temperature sensors, and the measurement of the temperature of the tissue at least every 33 ms comprises calculating via the temperature module the maximum measured temperature value of the plurality of temperature sensors; and   the power control module is configured to cease or reduce the ablation energy delivered, when the maximum measured temperature received from the temperature module reaches or exceeds a threshold temperature.   
     
     
         14 . The system of  claim 13 , wherein the threshold temperature is 100 C. 
     
     
         15 . The system of  claim 12 , wherein the power control module is configured to monitor impedance of the tissue over time, and to cease delivery of the ablation energy to the ablation electrode when the impedance exceeds a threshold value.